The present invention relates to a transmission with integrated brake particularly but not exclusively usable for vehicles.
Indoor transport vehicles, such as for example forklift trucks, normally use electric motor units, each of which, when coupled to a transmission, forms a drive unit.
The transmissions suitable for these drive units include the one disclosed by patent DE 4010742.
This transmission has, in an oil-bath casing, an epicyclic reduction unit which is connected, by means of a driven gear which is coaxial thereto and axially movable, to a pinion keyed on the driving shaft.
A disk brake is arranged between the epicyclic reduction unit and the driven gear and its disks are alternately coupled so as to rotate together with the former or with the latter.
Packing of the disk brake is achieved by means of a thrust pin which acts on the driven gear, moving it axially.
More in particular, one disk holder is fixed to the driven gear and one disk holder is integrated with an internally-toothed ring gear of the epicyclic reduction unit, whereas the pushers act in contrast with a spring resting against the sun gear of the reduction unit.
Although it is appreciated because of the numerous advantages it has with respect to the known art, this transmission is nevertheless not free from drawbacks, including the one due to the considerable thrust forces required to move the driven gear and pack the disks of the brake.
Another drawback is due to the fact that it is not possible to use helical teeth for the pinion and for the driven gear.
Another equally significant drawback is due to the fact that the oil contained in the casing is unable to dissipate the heat produced by braking.
Furthermore, the contrast spring, which rests on the planet gears of the reduction unit, has been found to be a hardly optimum solution for the good operation of the gears.